Top driven material shearing mixer and aerator

ABSTRACT

A portable unit supported in or on a body of fluent material activates a shear zone within the material into which a treating medium is injected under pressure. The shear zone is activated by counter-rotating rotors having projections through which the treating medium is discharged. The rotors are driven from a support by concentric shafts enclosing flow passages conducting the treating medium to the rotors.

United States Patent 1 91 White 1 1 TOP DRIVEN MATERIAL SHEARING MIXERAND AERATOR [76] inventor: Robert W. White, 409 S. Union Ave., P.O. Box74, Salem, Ohio 44460 22 Filed: Aug. 21, 1970 21 Appl. No.: 65,969

Related US. Application Data [63] Continuation-impart of Ser. No.851,702, Aug. 20,

[52] us. Cl 261/87, 261/93,-261/120, 259/5, 210/219 [51] Int. Cl.B01t3/04, BOlf 7/32 [58] Field of Search 2 1/30, 87, 91, 93,

261/120; 259/5; 210L2 1&242

[56] 7 References Cited UNITED sTATEs PATENTS 2,612,358 9/1952 0611161.... 261/93 3,491,880 1/1970 1166162.... 261/87 2,767,965 10/1956 Daman261/93 2,343,274 3/1944 Bailey,.lr. et a1 261/93 OOOOOOOO 1 Dec. 18,1973 3,400,918 9/1968 MacLaren 261/87 3,189,334 6/1965 Bell 26l/932,928,661 3/1968 MacLaren.... 26l/93 2,390,111 12/1945 Logue 261/932,590,581 3/1952 Shir1ey....'.. 261/93 2,863,681 12/1958 Robbins......'277/34 2,324,018 7/1943 Peterson 261/93 2,780,360 2/1957 Bon et a1.210/219 Primary Examiner-Tim R. Miles Assistant Examiner-Steven H.Markowitz Att0meyClarence A. OBrien and Harvey B. Jacobson 157 iABSTRACT A portable unit supported in or on a body of fluent materialactivates a shear zone within the material into which a treating mediumis injected under pressure. The shear zone is activated by counterrotating rotors having projections through which the treating medium isdischarged. The rotors are driven from a support by concentric shaftsenclosing flow passages conducting the treating medium to the rotors.

15 Claims, 6 Drawing Figures PATENIEU um 1 8 ms SHEET 1 OF 3 O O O O O OO 0 0 0 0 0 0 0 0 0 m 0. 0

Fig.

* 96 Robert m white aofim A Home TOP DRIVEN MATERIAL SHEARING MIXER ANDAERATOR This application is a continuation-in-part of my priorco-pending application U. S. Ser. No. 85l,702, filed Aug. 20, 1969 andrelates to the treatment of waste materials. I

There is presently a need for control of pollution in rivers, streams,lakes, harbors and the shores of the ocean resulting from such sourcesas sewage treatment plants, chimney wastes, pulp mills, mine drainage,oil spillage and other sources of industrial wastes. Waste materialsfrom the foregoing sources may be treated in accordance with the methodas disclosed and claimed in my prior co-pending applicationaforementioned. However, in view of the wide variety of uses for thistreating method and the many diverse areas or locations where treatmentis required, a mobile or portable type of treating apparatus would bemost desirable in connection with any extensive anti-pollution program.

In accordance with the present invention, a portable treating apparatusfor filling the aforementioned need is provided, one embodiment of whichfeatures a floating support carrying the powering equipment andpressurized fluid source or supply conduit equipment on top. Aconcentric shaft assembly extending downwardly from the floating supportinto the material being treated, mounts counterrotating rotors at thelower end having confronting faces with shear projection clustersmounted thereon as disclosed in my prior copending application for'thepurpose of establishing an active shear zone when the rotors arepowered. A treating medium such as gas, liquid or finally divided solidsor mixtures thereof, is injected into the shear zone through orifices inthe projection clusters which are in fluid communication through therotor bodies with flow passages in the concentric shaftassemblyconducting the treating medium from a pressurized source locatedon top of the floating support.

The present invention also contemplates the mounting of the portableapparatus by meansof its support in an inverted position within achimney stack for example, in order to treat flue gas and other airborneexhausts.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forminga part hereof, whereinlike numerals refer to like parts throughout, and in which:

FIG. 1 is a side sectional view through a typical apparatus constructedin accordance with the present invention with parts shown in verticalelevation.

FIG. 2 is an enlarged partial sectional view of a portion of theapparatus shown in FIG. 1.

FIG. 3 is an enlarged partial sectional view of a sealing unit in theapparatus shown in FIG. 1.

FIG. 4 is a transverse sectional view taken substantially through aplane indicated by section line 4-4 in FIG. 2.

FIG. 5 is a somewhat diagrammatic vertical sectional view throughanother form of treating apparatus constructed in accordance with thepresent invention.

FIG. 6 is a partial sectional view illustrating an alternate form ofsealing unit.

Referring now to the drawings in detail, and initially to FIG. 1,treating apparatus generally referred to by reference numeral 10 isshown. The apparatus includes a support platform 12 which is shownsomewhat diagrammatically and adapted to provide a floating support forthe entire apparatus on the material to be treat ed, which may forexample be a body of polluted water in a lake, pond, river, etc., orsewage in a treating pond. Thus, the support platform 12 may enclosehollow ballast tanks or be made of a flotation material such asstyrofoam plastic.

A mounting frame assembly 14 may be secured to the top of the floatingplatform 12 and provided with lift rings 16 on top thereof to facilitatetransport of the apparatus from place to place. The mounting frameprovides support on top of the floating platfonn 12 for a pair of primemovers in the form of drive motors 16 and 18. In one form of theinvention the supporting platform 12 also mounts an air compressorassembly 20 connected by means of a conduit 22 to a pressure storagetank 24 which is thereby charged with compressed air which is fed by asupply line 26 and branch lines 28 and 30 to the upper end of a verticalshaft assembly 32 through a pair of special, high pressure sealing units34 and 36 designed to prevent leakage of expensive gases such as ozone.Theshaft assembly is supported on'the mounting frame assembly 14 bymeans of pillow block bearingassemblies 38, 40 and 42 secured to themounting frame assembly above the support-platform 12.

The shaft assembly 32 includes an outer shaft 44 that ported by radialspokes that extend inwardly from a foraminous or perforated cylindricalbaffle housing 52 enclosing rotor assembly 54. The housing 52 issuspended from the lower end of a diametrically smaller and imperforatetube 56 whichis secured toand depends from the support platform 12 todirect downflow of influent in concentricrelation to the shaft assembly32. Supporting rods or spokes 58 position an intermediate bearingassembly 60 which rotatably supports the outer shaft 44 in itsconcentric position within the tube 56. The tube is provided withcircumferentially spaced recirculating ports--62 adjacent the upper endand is also provided with an injection tube 64 through which additionaltreating medium may be introduced to the tube for mixing with air andthe material being treated.

The rqtor assembly includes an upper flow dispersing rotor or impeller66 having vanes as disclosed in my prior copending application exceptfor a small pitch to axially impel material downwardly. The impeller 66is secured to the lower end of the outer shaft 44 and a lower flowdirecting rotor or impeller 68 is secured adjacent to the lower end ofthe inner shaft 46 in vertically spaced relation to the upper rotor 66so as to establish a shear zone 70 between the confronting faces 72 and74 of the rotors as described in my prior copending applicationaforementioned. Thus, the confronting convex face 72 of the rotor 66 andconcave face 74 of the rotor 68 as well as the lower curved face 76 ofthe rotor 68 are provided with clusters of studs 78 radially spaced fromthe rotational axis of the impeller having orifice ports through whichthe treating medium is discharged and distributed within the shear zoneas described in detail in my prior co-pending applicationaforementioned. When the rotors 66 and 68 are rotated in oppositedirections, the shear zone 70 will be activated in order to enhance theaction of the treating medium introduced into the material beingtreated, some of which is displaced radially outwardly and baffled bythe foraminous housing 52 through which the mixture of treated materialand treating medium flows. Some of the mixture may also flow upwardlyoutside of the imperforate influent tube 56 and enter through therecirculating ports 62. The diffusion and baffling of the mixtureflowing radially outward may also be effected by means of an outerperforated cylindrical wall 80 which is secured to and depends from thesupport platform 12.

An annular support 82 is secured to the lower edge of the outercylindrical wall 80 while an annular support foot 84 is secured to thelower edge of the cylindrical housing 52 enclosing the rotor assembly 54and the shear zone 70 established between the upper and lower rotors. Aflow disperser rotor 86 may also be secured to the outer shaft 44 of theshaft assembly and provided on its upper beveled face 88 with shearingstuds 90 through which treating medium is discharged as disclosed in myprior copending application aforementioned. A screen 92 may be securedto the bottom of I the housing 52 in order to enclose the rotor assemblyand the bearing 48 and protect these parts from larger solids that mayhave settled within the body of fluent material being treated. Further,in order to stir up settled material, a circular air manifold 94 may bemounted below the screen 92 and provided with outlet apertures 96through which air under pressure is discharged in a horizontal plane. Asupply conduit 98 is therefore connected between the manifold 94 and theoutlet conduit 22 supplying air under pressure from the air compressorto the storage tank 24.

As clearly shown in FIG. 1, the upper rotor 66 isdiametrically equal toor less than the inside diameter tube 56 to insure that all oftheinfluentexiting from the lower end of tube '56 contacts the lowerrotor 68. The lower rotor 68 on the other hand extends radially beyondthe upper rotor within the housing 52 which is diametrically larger thanthe influent tubes 56 so that excessive turbulence will occur outside ofthe tube 56. The material being treated will be activated within theshear zone 70 within which his mixed with air and other treating mediathat may be introduced through the tube 64. A downwardly pitched turbineblade 100 is secured to the outer shaft 44 partially submerged withinthe material being treated and covered by a baffle plate structure 102in order .to entrain air into the influent for partial aeration.

As hereinbefore indicated, the rotors 66 and 68 are rotated in oppositedirections. To this end, the drive motor 16 is drivingly connectedthrough a belt drive 104 to the inner shaft 46 from an upwardlyextending .motor shaft whereas the downwardly extending motor tofacilitate servicing of the apparatus as well as to avoid the necessityfor protective enclosure that would be necessary if the top mountedequipment were to be submerged within the material being treated. Thesealing units 34 and 36 must of course accommodate the supply oftreating medium under pressure where it be the compressed air as shownin the illustrated embodiment or any other treating medium supplied tothe counter-rotating drive shaft assembly 32.

As shown in FIG. 2, the sealing unit 34 includes a body 108 which isadapted to be fixed to the mounting frame and threadedly connected tothe inlet end 110 of the supply conduit branch 28. The inner shaft 46 ofthe shaft assembly 32 is adapted to be threadedly connected to an uppershaft section 1 12 that extends into the body 108 for fluidcommunication with a receiving chamber 114. The upper shaft section 112is journalled by a ball bearing assembly 1 l6 abutting a flange 118 onthe upper shaft section and held assembled by an internally threadedassembly cap 120 which compresses a sealing gasket 122, in wipingengagement with the upper section, between the shoulder 124 on the body108 and the annular spacing element 126.

The inner shaft also extends through the sealing unit 36 as shown inFIG. 3 into which the outer shaft 44 extends. The sealing unit 36includes a cylindrical stuffing box housing 128 that is provided with athreaded bore into which an inlet fitting 130 is inserted for connectionto the supply conduit branch 30. The fitting 130 is sealed to the houing128 by a packing seal 132 activated by a'packing nut 134. An annular endwall 136 is threadedly mounted in the top of the housing 128 andthreadedly receives an inner insert 138 axially abutting a radiallyinner sealing'gasket 140 to prevent leakage about the inner shaft 46. Astuffing box packing 142 in wiping engagement with the inner shaft 46 iscompressed or activated by a packing nut 144 threadedly received by theinsert section 138 to complete the sealing about the inner shaft. Thepacking 142 is in axial abutment with the upper end of a shaft extension146 which encircles the inner shaft above the .upper end of the outershaft and has a portion 148 securedto the upper end of the inner wall152 of the outer shaft. A cross-sectionally channel-shaped, flexible'seat 150 surrounds the extension 146 within the housing 128 in wipingengagement with the upper end of the outer shaft'44 and an inner tubularwall 152 of the outer shaft to which the lower section 148 of theextension 146 is secured. The gasket 150 in response to pressure engagesthe end wall 136 and thereby effectively seals vertical passages 154formed between the solid annular walls of outer shaft 44 including theinner tubular member. The flow conducting passage 154 are in fluidcommunication with the conduit section 30 through an annular receivingchamber 156 enclosed by the gasket 150. The inner tubular member 152 ofthe outer shaft is concentrically spaced from the outer wall byinterconnecting spokes 158 as more clearly seen in FIG. 4. The lowerend-of the housing 128 is sealed about the outer wall of the outer shaft44 by means of a packing 160 compressed by an annular channel member 162when assembled by the internally threaded packing nut 164. The channelmember 162 forms the outer race of a bearing assembly 166 through whichthe upper end of the outer shaft is journalled within the sealing unit36.

An alternate form of sealing unit 36' is illustrated in FIG. 6 whereinthe shaft extension 146 associated with the inner wall 152 of the outershaft 44 is replaced by a stationary sleeve portion 146' projectingdownwardly from the end wall 136 threadedly received in the top of unithousing 128 and axially overlapping the inner wall 152 of the outershaft. A sealing gasket 140' is seated in a recess formed in the endwall 136' and abuts the insert I38 which in turn is formed with a recessseating the packing 142' compressed by the packing unit 1441. As in thecase of sealing unit 36, the chamber 156' of unit 36 when pressurized byinflow of fluid to passage I54 expands the annular seal 150 into sealingengagement with the inner surface of housing 128' and the sleeve portion146' to prevent leakage from the outer shaft. Leakage along the innershaft on the outer hand is prevented by sealing gasekt 140' and packingIn the foregoing description, it will be apparent that treating mediumsuch as compressed air is introduced through the hollow air passage ofthe inner shaft 46 to the lower rotor 68 which is hollow and thereforeforms an air manifold from which the compressed air is dischargedthrough the orifices in the cluster of studs 78. The treating medium orpressurized air on the other hand is supplied to the upper rotor 66through the hollow walled outer shaft 44 enclosing the flow passages1154. A hollow wall-type of construction is utilized so that both thesealing units 34 and 36 may be located above the support platform 12 inorder to avoid servicing of sealing units immersed within the materialbeing treated. A simpler constructional arrangement may however providea flow conducting passage for the upper rotor formed directly betweenthe inner and outer shafts where high pressure leakage is not ascritical so that a solid walled outer shaft may be utilized. This typeof arrangement is shown in FIG.-5 wherein the apparatus is generallydenoted by reference numeral 168.

As in the case of the apparatus illustrated in FIG. I, apparatus 168includes a lower rotor 68' and an upper vaned rotor 66' to which thetreating medium is supplied for discharge from the cluster studs 78' onthe confronting faces 72 and 74'. The rotors are to be driven inopposite directions through a drive shaft assembly 32. The drive shaftassembly associated with the apparatus 168, however, includes a solidwalled outer shaft 44' enclosing an annular flow conducting passage 154'which communicates with the cluster studs 78' through outlet ports 170adjacent the lower ends of the outer shaft within the body of the rotor66'. The inner shaft 46' on the other hand encloses-an inner passage 172that is closed by the end wall 174 at the lower end of the inner shaftadjacent to which is formed outlet ports 176 in fluid communication withthe hollow body of the lower rotor 68'. The annular passage 154 isclosed at its lower submerged end within the body of the upper rotor 66by a gasket 178 that is activated by the packing nut 180 threadedlyreceived within a hub section 182 welded to the outer shaft 44'.

154' enclosed by the outer shaft 44' on the other hand, communicateswith another supply conduit branch 30' through the receiving chamber156' enclosed by a stuffing box 36" of any suitable type through whichthe inner shaft 46 extends. The outer shaft 44 may be driven by anysuitable source of motive power through a driven gear 184 secured to theouter shaft adjacent to the stuffing box 36".

From the foregoing description, many uses of the portable treatingapparatus will come to mind. For example, the apparatus may be utilizedon oxidation ponds and other such places which do not have sewagetreatment plants. Such oxidation ponds should be agitated to avoidsettling and also aerated. By means of the apparatus, such oxidationponds could also be seeded in order to encourage algae growth. Theapparatus of the present invention could also be utilized to inject atreating medium for homogeneous mixing of neutralizing acids, alkalis,oxygen, ozone, in connection with phenol wastes and other bodies ofindustrial wastes prior'to dumping into rivers or lakes. Treatment ofoil spillage or leakage into lakes, rivers, harbors and oceans may alsobe facilitated by the mobility of the apparatus of the presentinvention. Oil spillage may be treated, for example, by the apparatusutilizing detergents as the treating medium for emulsification purposesor by introducing finely divided plastic particles to attract the oiland causing it to sink to the bottom. Injection of bacteria, fertilizerand oxygen with the treating medium for initial bacterial growth mayalso be taken advantage of with the apparatus of the present inventionfor bacteria digestion of oil spillage.

Thus, the apparatus of the present invention may be mounted andinstalled as a mobile or portable unit in a variety of ways including,for example, floating thereof as a raft, anchoring at influent openingsin ponds, and by anchoring o'r towing to mouths of streams or rivers andat overflow spillage locations associated with industrial installations.The apparatus may also be mounted in special wells of boats or severalof the units may be mounted in a floating arrangement between thesupport hulls of a catamaran type of boat for multi-stage treatment ofmaterial by connecting the effluent discharge pipe of one unit with theinfluent pipe of the following unit. In this usage of the apparatus, theouter wall enclosure would have to be imperforate and provided with animperforate bottom whereby effluent is conducted from the top peripheryof one unit into the center influent tube of a following unit into whichit is introduced as the influent. In connection with the introduction offinely divided solids as a treating medium, activated charcoal may beutilized for sewage treatment together with a carrier gas such as air,oxygen or ozone.

In connection with the various aforementioned uses of the apparatus andthe structural arrangement of the apparatus as hereinbefore described,several factors contribute to the efficient operation of the materialtreating method. A high centrifugal shear is induced by the lower. rotorthrough the shearing studs aforementioned and internal shear created bythe studded counter-rotating upper disperser rotor driven at a variablespeed for controlled radial outflow. Injection of the treating mediumwhether it is gas, liquid orfinely divided solids, through the studcluster orifices, is of course one of the important aspects of theinvention when injection is effected while the shear zone between therotors is activated by counter-rotation of the rotors. The apparatusdisclosed in the present invention is a particularly desirableimprovement because of the type of mounting and mounting of power meansand pressurized medium supply equipment on an accessible side of thesupporting platform as hereinbefore indicated.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention.

I claim:

1. Apparatus for treating a body of fluent material comprising asupport, a vertically elongated drive shaft assembly rotatably mountedby the support and extending downwardly therefrom into the fluentmaterial, rotor means connected to the shaft assembly vertically spacedbelow the support to form a shear zone within the fluent material, powermeans mounted only above the support and drivingly connected to theshaft assembly for imparting rotation to the rotor means to activatesaid shear zone, means connected to the shaft assembly above the supportfor injecting a treating medium into the shear zone through the shaftassembly and the rotor means, a downflow tube depending from the supportenclosing the shaft assembly above the rotor means, and an aeratingblade connected to the shaft assembly partially immersed within thefluent material and baffle means fixed to the support above the fluentmaterial in operative relation to the blade.

2. The combination of claim 1 wherein said support is a flotation devicecarrying the power means and the medium injecting means above thesurface of the fluent material.

3. The combination of claim 1 wherein said rotor means comprises anupper flow dispersing member at most diametrically equal to theimperforate tube and a lower flow directing member diametrically largerthan the imperforate tube, said members having confronting faces betweenwhich the shear zone is formed, and material shearing projections onsaid faces having outlet orifices through which said treating medium isdischarged into the shear zone.

4. The combination of claim 3 including a flow dispersing rotor mountedon the shaft assembly within the imperforate tube.

5. The combination of claim 4 wherein said shaft assembly includes aninner shaft enclosing a first flow passage for the treating medium andan outer shaft enclosing a second flow passage for the treating medium.

6. The combination of claim 5 wherein said inner and outer shafts arerespectively connected to the lower flow directing member and the upperflow dispersing member transmitting counter-rotational movement to saidmembers.

7. The combination of claim 6 wherein said support is a flotation devicecarrying the power means and the medium injecting means above thesurface of the fluent material.

8. The combination of claim 7 wherein said medium injecting meansincludes a source of gas under pressure, and pressure sealed meansconnecting said source to the inner and outer shafts for fluidcommunication with said first and second flow passages.

9. The combination of claim 8 wherein said outer shaft is formed by ahollow annular wall within which the second flow passage is formed.

10. Apparatus for treating a body of fluent material comprising asupport, a vertically elongated drive shaft assembly rotatably mountedby the support and extending downwardly therefrom into the fluentmaterial, rotor means connected to the shaft assembly vertically spacedbelow the support to form a shear zone within the fluent material, powermeans mounted only above the support and drivingly connected to theshaft assembly for imparting rotation to the rotor means to activatesaid shear zone, and means connected to the-shaft assembly above thesupport for injecting a treating medium into the shear zone through theshaft assembly and the rotor means, said shaft assembly including innerand outer shafts driven relative to each other by the power means andrespectively enclosing flow passages for the treating medium, said rotormeans including a pair of impellers respectively connected to said innerand outer shafts and a sealing unit mounted on the inner shaft throughwhich the treating medium is conducted from the injecting means into theflow passage enclosed by the outer shaft.

1 l. The combination of claim 10 wherein said sealing unit includes anouter housing enclosing one end of said outer shaft, a removable endwall mounted by the housing in axially spaced relation to said one endof the outer shaft, packing means mounted by the end wall about theinner shaft, and pressure responsive sealing means enclosed by thehousing in abutment with the end wall for sealing a receiving chamberestablishing fluid communication between the flow passage enclosed bythe outer shaft and the injecting means.

12. The combination of claim 11 wherein the outer shaft includes innerand outer walls between which one of the flow passages is formed, theinner wall having an extension in wiping engagement with the pressureresponsive sealing means.

13. The combination of claim 11 wherein the end wall is provided with aradially inner sleeve surrounding the inner shaft in overlappingrelation to the outer shaft and in engagement with the pressureresponsive sealing means.

14. Apparatus for treating a body of fluent material comprising asupport, avertically elongated drive shaft assembly rotatably mounted bythe support and extending downwardly therefrom into the fluent material,rotor means connected to the shaft assembly vertically spaced below thesupport to form a shear zone within the fluent material, power meansmounted only above the support and drivingly connected to the shaftassembly for imparting rotation to the rotor means to activate saidshear zone, means connected to the shaft assembly above the support forinjecting a treating medium into the shear zone through the shaftassembly and the rotor means, and a downflow tube depending from thesupport enclosing the shaft assembly above the rotor means, said rotormeans comprising an upper flow dispersing member at most diametricallyequal to the downflow tube and a lower flow directing memberdiametrically larger than the downflow tube, said membe'rs havingconfronting faces between which the shear zone is formed, and materialshearing projections on said faces having outlet orifices, through whichsaid treating medium is discharged into the shear zone.

15. The combination of claim 14 wherein said inner and outer shafts arerespectively connected to the lower flow directing member and the upperflow dispersing member transmitting counter-rotational movement to saidmembers.

1. Apparatus for treating a body of fluent material comprising asupport, a vertically elongated drive shaft assembly rotatably mountedby the support and extending downwardly therefrom into the fluentmaterial, rotor means connected to the shaft assembly vertically spacedbelow the support to form a shear zone within the fluent material, powermeans mounted only above the support and drivingly connected to theshaft assembly for imparting rotation to the rotor means to activatesaid shear zone, means connected to the shaft assembly above the supportfor injecting a treating medium into the shear zone through the shaftassembly and the rotor means, a downflow tube depending from the supportenclosing the shaft assembly above the rotor means, and an aeratingblade connected to the shaft assembly partially immersed within thefluent material and baffle means fixed to the support above the fluentmaterial in operative relation to the blaDe.
 2. The combination of claim1 wherein said support is a flotation device carrying the power meansand the medium injecting means above the surface of the fluent material.3. The combination of claim 1 wherein said rotor means comprises anupper flow dispersing member at most diametrically equal to theimperforate tube and a lower flow directing member diametrically largerthan the imperforate tube, said members having confronting faces betweenwhich the shear zone is formed, and material shearing projections onsaid faces having outlet orifices through which said treating medium isdischarged into the shear zone.
 4. The combination of claim 3 includinga flow dispersing rotor mounted on the shaft assembly within theimperforate tube.
 5. The combination of claim 4 wherein said shaftassembly includes an inner shaft enclosing a first flow passage for thetreating medium and an outer shaft enclosing a second flow passage forthe treating medium.
 6. The combination of claim 5 wherein said innerand outer shafts are respectively connected to the lower flow directingmember and the upper flow dispersing member transmittingcounter-rotational movement to said members.
 7. The combination of claim6 wherein said support is a flotation device carrying the power meansand the medium injecting means above the surface of the fluent material.8. The combination of claim 7 wherein said medium injecting meansincludes a source of gas under pressure, and pressure sealed meansconnecting said source to the inner and outer shafts for fluidcommunication with said first and second flow passages.
 9. Thecombination of claim 8 wherein said outer shaft is formed by a hollowannular wall within which the second flow passage is formed. 10.Apparatus for treating a body of fluent material comprising a support, avertically elongated drive shaft assembly rotatably mounted by thesupport and extending downwardly therefrom into the fluent material,rotor means connected to the shaft assembly vertically spaced below thesupport to form a shear zone within the fluent material, power meansmounted only above the support and drivingly connected to the shaftassembly for imparting rotation to the rotor means to activate saidshear zone, and means connected to the shaft assembly above the supportfor injecting a treating medium into the shear zone through the shaftassembly and the rotor means, said shaft assembly including inner andouter shafts driven relative to each other by the power means andrespectively enclosing flow passages for the treating medium, said rotormeans including a pair of impellers respectively connected to said innerand outer shafts and a sealing unit mounted on the inner shaft throughwhich the treating medium is conducted from the injecting means into theflow passage enclosed by the outer shaft.
 11. The combination of claim10 wherein said sealing unit includes an outer housing enclosing one endof said outer shaft, a removable end wall mounted by the housing inaxially spaced relation to said one end of the outer shaft, packingmeans mounted by the end wall about the inner shaft, and pressureresponsive sealing means enclosed by the housing in abutment with theend wall for sealing a receiving chamber establishing fluidcommunication between the flow passage enclosed by the outer shaft andthe injecting means.
 12. The combination of claim 11 wherein the outershaft includes inner and outer walls between which one of the flowpassages is formed, the inner wall having an extension in wipingengagement with the pressure responsive sealing means.
 13. Thecombination of claim 11 wherein the end wall is provided with a radiallyinner sleeve surrounding the inner shaft in overlapping relation to theouter shaft and in engagement with the pressure responsive sealingmeans.
 14. Apparatus for treating a body of fluent material comprising asupport, a vertically elongated drive shaft assembly rotatably mountedby the support and extenDing downwardly therefrom into the fluentmaterial, rotor means connected to the shaft assembly vertically spacedbelow the support to form a shear zone within the fluent material, powermeans mounted only above the support and drivingly connected to theshaft assembly for imparting rotation to the rotor means to activatesaid shear zone, means connected to the shaft assembly above the supportfor injecting a treating medium into the shear zone through the shaftassembly and the rotor means, and a downflow tube depending from thesupport enclosing the shaft assembly above the rotor means, said rotormeans comprising an upper flow dispersing member at most diametricallyequal to the downflow tube and a lower flow directing memberdiametrically larger than the downflow tube, said members havingconfronting faces between which the shear zone is formed, and materialshearing projections on said faces having outlet orifices through whichsaid treating medium is discharged into the shear zone.
 15. Thecombination of claim 14 wherein said inner and outer shafts arerespectively connected to the lower flow directing member and the upperflow dispersing member transmitting counter-rotational movement to saidmembers.